1. Field of the Invention
The present invention relates to golf clubs, and more particularly to clubs that resist movement that would induce a hook or a slice in a golf ball struck with the club.
2. Background
Proper alignment between a golf ball, a golf club, and a golfer is the key to hitting the ball along a straight path. Even slight misalignment can induce an undesirable spin in the ball, causing it to veer dramatically to the inside (hooking) or to the outside (slicing). To avoid these undesirable consequences, the golfer must strike the club face squarely through the ball, by smoothly drawing the club downward through an arc without rotating the club shaft about its longitudinal axis.
Regrettably, it would seem that this movement is not natural for most golfers, and years of practice are necessary to enable them to reproduce this stroke with any degree of regularity. Unsurprisingly, many inventors have turned their minds to mechanisms for training golfers to reproduce such a stroke or for urging clubs to follow a desired swing-path.
For example, U.S. Pat. No. 2,626,151 granted in 1953 for a xe2x80x9cGolf Practice Apparatusxe2x80x9d illustrates a complicated combination of wheels, shafts, and restraints for causing a golfer to adopt a predetermined stance and to swing a club through a predetermined path. Unfortunately, the ""151 apparatus appears both cumbersome and complicated and is ill-adapted for use on an actual golf course.
It is also well known to attach to, or incorporate into, a golf club shaft either a fin for introducing aerodynamic drag or an airfoil for introducing aerodynamic lift. These devices are intended to alter the path of a golf club in various ways that the inventors imagine to be advantageous. Examples include U.S. Pat. No. 5,335,918 granted to Thomas J. Rupnik et al on Aug. 9, 1994 for a xe2x80x9cGolf Club Swing Training Devicexe2x80x9d, U.S. Pat. No. 5,571,048 granted to Lawrence D. Kenney on Nov. 5, 1996 for a xe2x80x9cGolf Swing Practice Devicexe2x80x9d, U.S. Pat. No. 5,310,188 granted to Joseph G. Hernberg on May 10, 1994 for a xe2x80x9cGolf Club Swing Alignment Devicexe2x80x9d, and U.S. Pat. No. 5,415,406 granted to Roy A. Reichenbach et al on May 16, 1995 for a xe2x80x9cGolf Club Swing Training Devicexe2x80x9d. Unfortunately, each of these devices is quite large with respect to the golf club itself. The fins and airfoils are generally elongated and extend along a substantial portion of the shaft in order to achieve whatever aerodynamic effect is desired. The devices are thus cumbersome and ill-suited for use during a golf game, and generally tend to make the golfer appear foolish.
Less obtrusive airfoils are also known and are generally incorporated into the head of a golf club. Examples of such airfoils includes those taught in U.S. Pat. No. 5,318,297 granted to Stephen Davis et al on Jun. 7, 1994for a xe2x80x9cGolf Clubxe2x80x9d and in U.S. Pat. No. 5,511,786 granted to Anthony J. Antonious on Apr. 30, 1996 for a xe2x80x9cWood Type Aerodynamic Golf Club Head Having an Air Foil Member on the Upper Surfacexe2x80x9d. Such airfoils are asserted either to affect the elevation of the club head or to reduce the drag of the club head, to permit it to be swung at a higher velocity. These airfoils are not configured to resist rotation of the shaft.
What is needed therefore, is an unobtrusive device for urging a golf club along an appropriate path when swung by a golfer, and in particular to resist rotation of the golf club shaft along its longitudinal axis.
The present invention is directed to such a solution.
In one embodiment of the present invention, a small fin extends radially from the neck portion of a golf club head. The fin is aligned relative to the club head so as to produce minimum drag when the club is drawn smoothly through the desired arc without rotating the club shaft about its longitudinal axis. Rotation of the shaft about its longitudinal axis displaces the fin from its minimum drag position and hence puts the fin in disequilibrium, such that the drag is greater on the side of the fin that would urge the fin back into its equilibrium position, thereby rotating the shaft back into its correct position.
The fin may be located generally on the club head or shaft; however, desirably it is located on the neck portion of the club head for a number of reasons. First, the club head travels faster than the rest of the club during a golf swing and hence a small fin so located can generate a larger aerodynamic effect than one placed elsewhere, for example on the shaft. Second, this location is a pivot point between the shaft and the head, so that fine adjustments at this pivot point will compensate for larger displacements in the club head or shaft. Third, this location permits the fin to be rotated about the longitudinal axis of the shaft to adjust for a golfer""s particular swing characteristics.